A generic strut for a motor vehicle with an axially adjustable spring plate is described in DE 10 2005 001 742 A1. The disclosed strut comprises essentially a vibration damper with a cylinder and a piston rod which is supported to be able to move axially therein, a support spring which is dynamically connected to the spring plate, a ring electric motor with a rotor and a stator which is dynamically connected via its motor housing to the piston rod, as well as a ball screw with a threaded spindle which is pivoted on the piston rod, and a threaded nut. The strut is fixed on the vehicle body by way of a bearing arrangement, the bearing arrangement having spherical bearing surfaces which allow at least a pivoting motion of the strut to the vehicle body. The axial adjustment of the spring plate can be effected by the rotor being dynamically connected to the threaded spindle and the spring plate being dynamically connected to the threaded nut so that rotary motion of the rotor which has been initiated by the ring electric motor causes translational motion of the spring plate.
In this connection, the disadvantage is the circumstance that the piston rod is pivoted both in the bearing arrangement and also in the damper and that the motor housing which surrounds the stator is connected to the piston rod, that is, both the stator with the motor housing and also the rotor are not fixed with respect to the degree of rotational freedom. The consequence of this is that the reaction moments of rotary driving are not supported and the components can turn randomly to one another.
The object of the invention is to develop a strut for a motor vehicle with an axially adjustable spring plate while avoiding the indicated disadvantages such that support of driving moments is ensured.